Find the sum S18 of the first 18 terms of the arithmetic sequence −12, −9.5, −7, −4.5, …
Sequences & series worksheet with answers
1.Easy
a₁ = −12d = 2.5n = 18
S18 =
2.Easy
Find the sum S15 of the first 15 terms of the arithmetic sequence 12, 12.5, 13, 13.5, …
a₁ = 12d = 0.5n = 15
S15 =
3.Medium
Find the radius of convergence R of the power series Σk=1∞ (1/2)ᵏ·xᵏ/(k + 1).
Σ (1/2)ᵏ·xᵏ/(k + 1)x₀ = 0
R =
4.Medium
Exactly one of the four series converges. Click it.
A: Σ (5/4)ᵏB: Σ (1/3)ᵏC: Σ k!/10ᵏD: Σ (1 + 1/k)ᵏ
- 1A: Σ (5/4)ᵏ
- 2B: Σ (1/3)ᵏ
- 3C: Σ k!/10ᵏ
- 4D: Σ (1 + 1/k)ᵏ
5.Hard
f(x) = sin x is approximated by its Maclaurin polynomial of degree 3 at x = 0.3. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = 1 to find the largest possible error |R₃|.
f(x) = sin xn = 3x = 0.3M = 1
|R₃| =
6.Hard
f(x) = cos x is approximated by its Maclaurin polynomial of degree 5 at x = 0.8. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = 1 to find the largest possible error |R₅|.
f(x) = cos xn = 5x = 0.8M = 1
|R₅| =
Answer key
- 1. S18 = 166.5
- 2. S15 = 232.5
- 3. R = 2
- 4. B: Σ (1/3)ᵏ
- 5. |R₃| = 0.0003375
- 6. |R₅| = 0.0003641
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